Fuse



Aug. 13, 1929. J. P. ARNDT ET Al.

FUSE

FledSept. 20, 1926 2 Sheets-Sham Aug. 13, 1929. J. P. ARNDT ET AL FUSE 2 ISheets-Sheet 2 Filed sept. 2o, 1926 gwuentozs' Patented Aug. 13, 1929.

UNITED -STATES PATENT OFFICE.

JOHN r. AENDT AND JO'sErHw. LELIVELT, JE., OE CLEVELAND, omo, AssIeNoEs To TEE LINE EQUIPMENT sALEs COMPANY, OE CLEVELAND, OHIO, A CORPORATION F OHIO.

FUSE.

Application led September 20, 1926. Serial No. 136,466.

This invention relates to fuse for e'lectrical circuits in which a wire fuse link or other vaporizable conductor gives way under the heating action of the current passing through it andbreaks the circuit whenever the current eXceeds'a definite amount.

The present invention has for an object to provide a fuse in which short circuiting and reformation of an arc between the terminals is prevented.

A further object is to provide a fuse in which the gases generated in the fusing of the link are discharged in suchmanner that they cannot form a conducting path between the terminals.

A further object is to provide a fuse having a casing of insulating material which is so reinforced that it will not be damaged by the pressure of gases generated when the fuse is blown. In addition, itl is 'the aim of the present invention to provide a fuse in which the casing is protected against damage by heat generated in the blowing of the fuse and in which the casing is protected against damage by prolonged heating of the fuse link to a temperature slightly below the' fusing point.

It is also an object o the invention to provide a fuse holder which can be readily disconnected from the line for replacement ofv the fuse and which. can be quickly and easily attached to or detached from its support.

With the above and other objects in View, the invention may be said to lcomprise the device as illustrated in the accompanying drawings hereinafter described and particularly set forth in the appended claims, together with such variations and modifications thereof as will be apparent to one skilled in the art to which the invention appertains.

Reference shouldrbe Ahad to the accompanying drawings forming a part of this specification, in which:

Fig. 1 is a vertical section through the fuse casing and support, the section being taken on the line indicated at 1-1 in Fig. 2;

Fig. 2 is a vertical section taken on the line indicated at 2-2 in Fig. 1;

Fig. A3 is a side elevation of the fuse ;A

Fig. 4 is a front elevation;

Fig. 5 is a bottom plan view;

Fig. 6 is a top plan view of a movable fuse casing showing the same in open position; and

Fig. 7 is a section taken on the line indicated at 7 7 in Fig. 2. In the accompanying drawings, the fuse is supporting bracket l adapted to be secured to a conductor supporting cross arm 2. The bracket 1 is adapted to rest upon the top of a cross arm and is provided with depending armsl 8 and 4 upon opposite sides of the cross arm, the arm 3 being provided with a set screw 5, by means of which the arm 4 may be drawn against the opposite side of the cross arm to clamp the bracket thereto. The depending arm 4 of the bracket is an elongated arm which extends downwardly and outwardly from the cross arm and is provided at its lower end with a laterally projecting pivot pin 6 to which is attached, near its outer end, a radially projecting retaining pm 7 for a purpose which will be hereinafter described.

To the upper portion of the arm 4 of the bracket there is rigidly secured a Contact supporting member 8 which is formed of insulating material such as porcelain, the member 8 being fixed to the arm 4 by means of suitable securing bolts 9. The contact supporting member 8 is provided at the top thereof with an outwardly projecting cover portion 10 and beneath the cover portion has rigidly attached thereto a pair of contact members 11, each consisting of a pair of resilient plates adapted to receive a knife switch blade between them. Each of the contact members 11 has riOidly secured thereto a terminal post 12 adbapted to receive a line wire, the terminals and Contact members being rigidly secured to the support 8 by means o suitable bolts 13.

A. movable fuse casing 14 is mounted beneath the fixed Contact su port 8 to swing upon the pivot pin 6 of) the supporting bracket and this movable casing is formed of a suitable insulating material 'such as porcelain. The casing 14 is provided with a rearwardly extending flange 15 which has a transverse cylindrical opening 16 adapted to fit upon the pivot pin 6 and a slot 17 extending radially from the o ening 16 through which the retaining pin?? may pass in one position of the casing 14 on the pivot pin 6. The radial slot 17 is so disposed that when the casing 14 is swung downwardly awa from the fixed contact support 8, the slot Il maybe aligned with the retaining pin 7 to shown mounted upon a suitable U-shaped' permit the casing 14 to be slipped onto or oi' of the pivot pin 6. rlhe casing 14 may be secured i'n its uppermost position in engagement with the fixed contact support 8 by means of a pivcted hook 18 which is carried by the casing 14 and adapted to engage with a pin 19 secured to the outer edge of the cover portion 10 of the fixed support. The casing 14 has a pair of switch blades 20, rigidly secured to the upper end thereof, which engage with the contact members 11 carried by the support member 8. i

The movable casing member 14 is provided with a pair of openings 21 extending longitudinally therethrough from the upper to the lower end, and in the upper ends of these openings are secured externally threaded tubular terminal posts 22 formed of suitable conducting material, such as brass or other copper alloy. The terminal posts pass through openings in the base flanges of the blade contacts 2() and are provided with nuts 23 by which the contacts 2O are clamped to the upper end of the casing 14. The terminal posts 22 extend into the openings 21 and on the lower ends thereof are secured reinforcing sleeves 24, which extend downwardly in the openings 21 below the lower ends of the tubular terminals 22 and terminate short of the lower end of the casing 14. The reinforcing sleeves 24 are formed of a suit.- able metal, preferably iron, and serve to protect thebody of the casing 14 against damage by the pressure of gases generated in the blowing of the fuse. A lining sleeve 25 of vitreous electrical insulating heat resisting and heat conducting material such as lava is secured within each of the openings 21 and each sleeve is provided with a reduced upper portion 26 which fits within the metal reinforcing sleeve 24 and terminates adjacent the lower end of the terminal post 22. The sleeves 24 and 25 are slightly spaced from each other and from the wall of the o ening 21 and the spaces between the s eeves and between the sleeves and wall are filled with a suitable cement 27 by which the sleeves are rigidly held in place. At the lower end of the casing 14, a groove 28 is provided between the lower ends of the openings 21 and in the lower ends of the sleevesv25 to provide a channel between the open lower ends-of the two chambers formed terminals 22 and serve toclamp the ends` of the link against the upper ends Vof the tubular terminal members 22 and to close l bers.

masses the upper ends of the spaced fuse chamrEhe fuse link 29 is preferably wire, formed of a suitable fusible metal and this wi-re has a single 4strand at each end within the tubular terminals 22 and a plurality of. strands in the portion intermediate the end portions within the tubularterminals 22. The closure rcaps 30 serve to seal the upper ends of the tubular members 22 so that gases generated in the fusion of the .link are prevented from escaping into the space between" the contact members of the switch. The fuse link 29 is so supported that the end portions thereof within the tubular terminals 22 are out of contact with the walls of the tube 22, while the portions of the link extending down through the sleeves 25 andalong the channel 28, at the lower end of the casing is substantialy in contact with the sleeves and easing. rlhe portions of the link 29, contacting with the sleeves 25 and with the intermediate portion of the casingy 14, Aare prevented from becoming excessively heated by a passage of a current therethrough by reason of the fact that the heat is conducted away from the fuse link by the walls in contact therewith. The end portions of the link 29, however, which are within the tubular terminals 22, are supported out of contact with the walls of the tubes and these portions of the link will, therefore, be heated to a higher temperature than the intermediate portions so that fusion will always occur within the tubes 22. The inter- 'ends of the sleeves 25 tothe upper ends of the tubular terminal members will-be held out of contact with the surrounding walls. The tubular members-22 thus form enlarged explosion chambers and the sleeves 25 form passages permitting.. the gases to be discharged from these` chambers through the lower ends of the casing. Since the two ex- Elosion or fusion chambers are separate and ave separate outlets at the lower end of the casing, the-gasesV generated in the fusion of the wire cannot pass to the contacts and establish a current across the same. The rupture of the fuse link in either or both of the chambers will create a gas pressure tending to blow the fuse wire out of the lower endsl of the chambers and prevent any reformation of the. arc between the fuse wire and terminals. The metal tubes 22 and 24 have sufficient strength to resist the pressure of the gases generated upon blowing the fuse and protect the casing 14 against damage by gas pressure. The casing is also protected against damage by continued heating of the fuse link to a temperature slightly below that lio of fusion by reason of the fact that the intermediate portions of the link are cooled by contact with the sleeves 25, which are of heat resisting material which will not be damaged by hot fuse wire in contact therewith.

Y In order to more effectively separate the switch Contact and prevent short circuiting between these contacts in the event that there should be `a leakage of metallic vapors past one vof the closure caps 30, the casing 14 is provided with a partition 31 which extends transversely between the terminal tubes-22 and engages with the cover portion 10 of the fixed. contact supporting member when the casing 14 is in switch closing position.

he partition 31 will prevent any substantial leakage of metal vapor from one terminal to the other in the space between the casing 14 and cover member 10, whenY the casing is in closed position. The line wires 32 are at tached to the terminal members 12, carried by the fixed support 8, and the circuit is closed between the terminals 12 by means of the knife switch members and the fuse link 29 and the mounting of the casing 14 is such that the knife switch may be opened and the fuse terminals may be brought to an accessible position by simply swinging the casing 14 about its pivot. If it is desired to remove the fuse casing 14, all that is necessary is to swing the casing downwardly until the slot 17 registers with the retaining pin 7 whereupon the casing14 may be slipped laterally olf of the supporting pivot pin 6.

Having thus described our invention, what we claim is:

1. In an electric fuse, a casing having a pair of tubular chambers, said chambersv being closed at one end and open. at the other, the chambers being enlarged adjacent their closed ends, terminals adjacent the closed ends of the chamber, and a'fuse link connected at its opposite ends to said terminals, said link extending lengthwise through the chambers and across the space between the open ends thereof, the link being in contact with the walls of the chambers in the reduced portions thereof and out of contact with the walls in the enlarged portions of the chambers adjacent the terminals.

2. In an electric fuse, a pair of terminals insulated from. each other, a fuse link connected to said terminals and a casing having a tubular metallic wall surrounding the link adjacent orte of the terminals, said casing being open at the end oppositethe latter terminal, said tubular wall being lined with vitreous material, for a portion of its length from the o )en end toward the terminali, and said fuse ink being supported in Contact with said lining and out of contact with said wall between the terminal .and the iined portion oi the casing,

3. In an eiectrie fuse, a casing having a tubular chamber closed at ene endand at the other, a portion of the casing being formed of electrical insulating heat conducting material, a terminal at the closed end of said chamber, a second terminal carried by the casing, and a fuse link connected to the terminals and extending through said chamber, said link being supported between the terminals with a portion thereof adjacent the first mentioned terminal out of Contact with the walls of the casing and a portion thereof between said first mentioned portion and the second terminal eX- tending along and in contact with the wall of said electrical insulating heat conducting portion of the casing.

4. In an electric fuse, a casing havingv a pair of tubular chambers, each closed at one end and open at the other, said chambers having wall portions formed of electrical insulating heat conducting material, terminals at the closedends of said chambers, and a fuse link connected at opposite ends to said terminals and extending through the chambers and across the space between the open ends thereof, said link having its end portions adjacent the terminals ont of contact with the chamber walls and intermediate portions extending along and in contact with the wall of electrical insulating heat conducting portions thereof.

5. In an electric fuse, a casing having a pair of terminals and ay pair of chambers one adjacent each. terminal, each closed at the end adjacent to the terminal and each 'chamber having an opening to the atmosportion formed of electrical insulating heat conducting material with which intermedik ate portions of said fuse link are in contact.'

7. In an electric fuse, a casing formed cf insulating material and having a pair of openings extending therethrough, a metallic tube secured in each of the openings at one end of the casing, a detachable cap upon the outer end ci each of said tubes and a fuse link having its opposite ends secured between said caps and tubes, said fuse link extending through. said tubes and openings.

8. In an electric fuse, a casing formed oi insulating material and having parallel openings extending longitudinally therethrough, terminals secured` the openings and positioned side by side .Y

the casing, closure members for ltheouter Y ends of the tubes, a lining of vitreous insutubes, said fuse link extending through the yes lating material covering the interiors of the inner end portions. of the tubes and a fuse link secured at its opposite ends between the closure members and the outer ends of the tubes and across the space between the open ends thereof, said link being supported out of contact with the tubes adjacent the closed ends thereof and in contact with said lining.

10. In an electric fuse, a casing formed of insulating material and provided with apair of openings extending longitudinally therethrough, metallic' tubes secured in the upper ends of the openings, metallic rein-` forcing'tubes lying within the openings and joined to the lower ends of said.first mentioned tubes, a lining of: vitreous material covering the inner'surface of each of said reinforcing tubes, a cap ada ted to be secured upon the-upper end o each of said first" mentioned tubes and a fuse link secured at` its opposite ends between the upper ends of said tubes and said cap, said link extending through the tubes and across the space between the open ends thereof, said link having'its end portions supported out of contact with lthe interior of the threaded tube and having intermediate portions engaging said vitreous lining.

11. An electric fuse comprising a bracket adapted to be attached to a conductor supporting cross arm, a member formed of insulating material and fixed to said bracket, a pair of contacts carried by said member, a fuse supporting member formed of insulating material pivoted on said bracket to swing toward and from said fixed member, a pair of contacts carried by said pivoted member and adapted to simultaneously engage the contacts on said fixed member, a fuse terminal secured to each of the contacts on the pivoted member, a fuse link connected at its opposite ends to said terminals, said fuse link being substantially U-shaped and extending from eachY of the terminals longitudinally through the pivoted member, and means for detachably securing the pivoted member in a position in which its contacts engage with the contacts of the fixed member. 4

12. A n electricalfuse comprising a fixed member formed of insulating material and having a pair of spacedcontacts secured thereto, a second member of insulating material pivotally mounted to swing toward and from said fixed member, said pivoted member having a pair of contacts adapted to simultaneously engage-with the contacts on the fixed member, a fuse link carried by the pivoted member and having its opposite ends connected with the contacts carried by the pivoted member and means for detachablyV securing the pivoted member to the fixed member with the contacts thereof in engagement with the contacts of the fixed member.

13. An electrical fuse comprising a supporting bracket, a member formed of insulating material fixed to said bracket, said member having spaced contacts secured to the underside thereof, a' second member formed of insulating material supported on said bracket to swing about a horizontal axis, said'second insulating member having a pair of spaced contacts adapted to simultaneously engage with the contacts on the fixed member, a fuse link carried by the pivoted member and connected at its opposite ends to said contacts on the pivoted member, and means for detachably securing the pivoted member in a position in which its contacts engage with the contacts of the fixed member.

14. An electrical .fuse comprising a supporting ,brackethaving a downwardly extending arm and a pivot pin fixed to said arm and extending laterally therefrom, a retaining pin fixed to said pivot pin and projecting laterally therefrom, a member formed of insulating material and fixed to the upper portion of said bracket, a pair of spaced contacts secured to the underside of said member, a. second member formed of insulating material and provided with a cylindrical transverse opening adapted toreceive said pivot pin and with a slot project-l ing radiallyV from said opening through which said retaining pin may pass, space/d contact members carried by said pivoted members and adapted to simultaneously engagel with the contacts-on the fixed member, a fuse link connected between the contacts lof the pivoted member, and means for detachably securing said pivoted member to the fixed member with the contactsthereof in engagement with the contacts of the fixed member.

15. In an electric fuse, a casing formed of insulating material and having a pair of openings extending longitudinally therethrough, a tubular terminal member secured in the upper end of each of said openings, a

closure member detachably secured upon the upper end of each tube, a reinforcing metallic tube secured upon the lower end of each of said first mentioned tubes and lying within said openings, said reinforcing tubes terminating short of the lower ends of said openings, a lining of vitreous material covering the interior of each of saidreinforcing tubes and the interior of said openings below the lower ends of said tubes, cementing material lling the space between said reinforc- Iing tubes and linings and the walls of said openings, and a fuse link secured at its opposite ends between said closure members and the upper ends of said tubular terminal members, said fuse linkextending through the tubes and openings and across the space between the lower ends of the openings.

16. In an electric fuse, a casing formed of insulating material and having a pair of openings extending longitudinally therethrough, a tubular terminal member secured in the upper end of each of said openings, a closure member detachably secured upon the upper end of each tube, a reinforcing metallic tube secured upon the lower end of each of said irstmentioned tubes and lying within said openings, said reinforcing tubes terminating short of the lower ends of said openings, a lining of vitreous material covering the interior of each of said reinforcing tubes and the interior of said openings below the lower ends of said tubes, cementing material filling the space between said reinforcing tubes and linings and the walls of said openings, and a fuse link secured at4 its opposite ends between said closure members and the upper ends of said tubular terminal members, said fuse link extending through the tubes and openings and across the space between the lower ends of the openings, said link being in engagement with said vitreous lining and having its opposite end portions within said tubular terminal members out of Contact with the interiors thereof.

17. In an electric fuse, a casing formed of a block of insulating material having a pair of openings extending longitudinally therethrough from the upper to the lower end thereof, and having a groove at its lower end extending between said openings, terminal members secured in the upper ends of said openings and closing the same, and a fuse link having its opposite en'ds secured to the terminal members and extending through said groove connecting the openings.

In testimony whereof, we hereunto ailiX our signatures.

JOHN P. ARNDT. JOSEPH W. LELIVELT, JR. 

